Process for recuperating rosin size already applied to papers



Patented Feb'. 27, 1934 UNITED V STATES PROCESS FORRECUPERATING ROSINSIZE ALREADY APPLIED TO PAPERS I Shigenarl Yano, Fulimachi, Fuiix'lm,

Shizuokaken, Japan No Drawing. Application September is, 1932 Serial No.633,543

2 Claims. (01. 92-1) The present invention relates to a process forrecuperatingrosin size already applied to various kinds of papers bymeans of very simple and easy operation without using chemicals.

5 Hitherto rosin-sized papers have never been produced without damagingthe size effect owing to various treatments after drying operation orthe latter itself. On this account, when strong size is desired in the.,case of machine-grazed paper, water-finished paper and the like, it isrequired to apply surface size of animal or vegetable origin. Thesurface size, however, often decomposes to emit an offensive smell anddegrade the appearance of the paper. Moreover, its aprlication requirescomplicated equipments and raises the cost of production. I

In accordance with the present invention, steam is applied, to therosin-sized paper before, during 'or after operation of either drying orother various treatments. The simultaneous actions of damping andwarming are effected by the simple operation of steaming. Thepresent'proc-' ess of recuperation may be effectively applied to allkinds of papers sized with preparations 5 containing rosin, especiallyto wrapping paper,

printing paper, Indian paper and the like.

' By the simple and eflective operation of steaming according to thepresent invention, rosin size contained in papers can be completelyrecuperated, water-proofing power, writing property, lustre, strengthand all other qualities and appearance being remarkably improved. And asexpansion and contraction of paper are extremely diminished, the processis especially favourable to print- 5 ing paper. Moreover, quantities ofrosin, alum and'other chemicals requisite for preparing size may bereduced to orunder one half by this invention.

In the preferred practie of the invention,

40 steaming is carried outat" 5-95 C. for about 1-30 minutes, usually 2minutes for most machine-grazed papers, the duration and temperaturebeing varied according to rosin content and kinds of qualities of papersto be treated. The

simplest operation in carrying out the present invention is injection ofsteam into a chamber containing the paper to be treated. Alternativeoperations, such as preliminary humidifying and indirect warming, may beadopted. Optimum o temperature varies from 65 C. to 90 C. and

preferable humidity ismore than 90%.

By wayof example, if a water-finished board, which is composed of 80% ofbleached sulphite pulp and 20% of ground pulp and sized with apreparation containing 1.5% (to the weight of pulp) of rosin, 2.5% ofalum, 1.5% of starch and 25% of clay, is treated inaccordance with thepresent invention with saturated steam at 55-60 C. for 5, 10, 15 and 30minutes respectively, maximum and minimum spreading breadths in mm. ofink line of 1.1 mm. original breadth are as follows: 7

0 min. 5 min. 10 min. 15min. 30 min.

Original breadth 1. l 1. l l. l 1. 1 l. 1 Minimum breadth 2. 4 2. 0 1.6 1. 3 1. 3 Maximum breadth 4. 0 3. 3 2. 6 2. 0 1. 9

And if a paper, which is composed of of ground pulp and 30% ofunbleached sulphite pulp and sized with a preparation containing 1.5% ofrosin and 4.0% of alum, is treated with saturated steam at 80 0.,

0 min. 5 min. 10 min.

Original breadth.-. l. l l. 1 1. 1 Minimum breadth.. 1. 8 1. 2 l. 2Maximum breadth- 4. 0 1. 3 1. 3

The steaming process accordingto the present invention may be easilycarried out in a continuous operation with paper-making process orvarious finishing processes.

As already explained hereinbefore, the main object of the inventionresides in the recuperation of the rosin size by means of very simpleand easy operation, wherefrom many advantages may be derived. Manydifllculties and obstructions due to rosin size in paper-makingoperations may be entirely avoided. As the applied rosin size can beeffectively and completely recuperated, even small -quantity of size issufficient, this fact being especially remarkable in the case of paperswhich can be'difiicultly sized. In carrying out the present inventionthe equipment is so simple and the operation is so easy that the costincreased bythe steaming can be sufliciently compensated by the savedcost of chemicals or other materials requisite for preparing rosin size.Moreover, quite differing from surface size, the recuperated rosin sizeis never decomposed and consequently neither damages the appearance ofthe paper nor emits a disagreeable odour.

I claim:

1. Process for recuperating the rosin size applied to paperscharacterized by the fact that rosin-sized paper is submitted tosteaming at 55-100 C. whereby the rosin size is simultaneously affectedby damping action as well as warm ing action.

2. Process for recuperating rosin size as claimed in claim 1, whichcomprises exposing the paper to steam and keeping thus treated paper inan enclosed chamber.

SHIGENARI YANO.

